3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
The 3GPP LTE may configure carrier aggregation (CA). In CA, two or more component carriers (CCs) are aggregated in order to support wider transmission bandwidths up to 100 MHz. A user equipment (UE) may simultaneously receive or transmit on one or multiple CCs depending on its capabilities.
When a UE is configured with a large number of carriers such as 16, the size of uplink control information (UCI) may also increase. Based on the current design of physical uplink control channel (PUCCH) (such as via PUCCH format 3), the number of UCI bits carried in a PUCCH is limited. Thus, when a network configures multiple carriers, a method for supporting the UCI with a large number of bits may be necessary. One example is to design a new PUCCH format which can include more UCI bits than the current PUCCH format. However, mechanisms to reuse the currently available PUCCH formats may also be considered.